Last millennium Northern Hemisphere summer temperatures from tree rings: Part II, spatially resolved reconstructions

Anchukaitis, Kevin J.; Wilson, Rob; Briffa, Keith R.; Büntgen, Ulf; Cook, Edward R.; D’Arrigo, Rosanne; Davi, Nicole; Esper, Jan; Frank, David; Gunnarson, Björn E.; Hegerl, Gabriele C.; Helama, Samuli; Klesse, Stefan; Krusic, Paul J.; Linderholm, Hans W.; Myglan, Vladimir S.; Osborn, Timothy J.; Zhang, Peng; Rydval, Miloš; Schneider, Lea; Schurer, Andrew; Wiles, Greg; Zorita, Eduardo

doi:10.1016/j.quascirev.2017.02.020

Cited by 199 publications

(301 citation statements)

References 228 publications

Supporting

Mentioning

290

Contrasting

Order By: Relevance

“…This framing allows us to highlight what is theoretically possible while also making falsifiable claims about what is impossible to reconstruct given current proxy networks. In our experiments we find that skill is highest in the tropics and in regions local to proxy sampling, in accordance with many previous pseudoproxy and real-proxy reconstructions that focused on temperature or other nonhydroclimate variables (e.g., Smerdon, 2012;Steiger et al, 2014;Hakim et al, 2016;Anchukaitis et al, 2017). For tree rings (which constitute the majority of annually resolved proxies) we also find that local reconstruction skill depends on the moisture or temperature sensitivity of particular treering proxies: moisture-sensitive trees are necessary for skillful PDSI or SPEI reconstructions, and temperature-sensitive trees are similarly necessary for skillful temperature reconstructions.…”

Section: Discussionsupporting

confidence: 91%

A pseudoproxy assessment of data assimilation for reconstructing the atmosphere–ocean dynamics of hydroclimate extremes

Steiger

Smerdon

2017

Clim. Past

View full text Add to dashboard Cite

Abstract. Because of the relatively brief observational record, the climate dynamics that drive multiyear to centennial hydroclimate variability are not adequately characterized and understood. Paleoclimate reconstructions based on data assimilation (DA) optimally fuse paleoclimate proxies with the dynamical constraints of climate models, thus providing a coherent dynamical picture of the past. DA is therefore an important new tool for elucidating the mechanisms of hydroclimate variability over the last several millennia. But DA has so far remained untested for global hydroclimate reconstructions. Here we explore whether or not DA can be used to skillfully reconstruct global hydroclimate variability along with the driving climate dynamics. Through a set of idealized pseudoproxy experiments, we find that an established DA reconstruction approach can in principle be used to reconstruct hydroclimate at both annual and seasonal timescales. We find that the skill of such reconstructions is generally highest near the proxy sites. This set of reconstruction experiments is specifically designed to estimate a realistic upper bound for the skill of this DA approach. Importantly, this experimental framework allows us to see where and for what variables the reconstruction approach may never achieve high skill. In particular for tree rings, we find that hydroclimate reconstructions depend critically on moisture-sensitive trees, while temperature reconstructions depend critically on temperature-sensitive trees. Realworld DA-based reconstructions will therefore likely require a spatial mixture of temperature-and moisture-sensitive trees to reconstruct both temperature and hydroclimate variables. Additionally, we illustrate how DA can be used to elucidate the dynamical mechanisms of drought with two examples: tropical drivers of multiyear droughts in the North American Southwest and in equatorial East Africa. This work thus provides a foundation for future DA-based hydroclimate reconstructions using real-proxy networks while also highlighting the utility of this important tool for hydroclimate research.

show abstract

Section: Discussionsupporting

confidence: 91%

A pseudoproxy assessment of data assimilation for reconstructing the atmosphere–ocean dynamics of hydroclimate extremes

Steiger

Smerdon

2017

Clim. Past

View full text Add to dashboard Cite

show abstract

“…Schweingruber, 1988;Briffa et al, 2002;Anchukaitis et al, 2013;Schneider et al, 2015), but such records do not yet exist for the GOA. MXD series are particularly desirable as such records often have stronger correlations with temperatures than RW and result in climate reconstructions with better skill and spectral fidelity (Anchukaitis et al, 2013;Esper et al, 2015;Wilson et al, 2016;Anchukaitis et al, 2017). This is partly because RW chronologies typically exhibit higher autocorrelation and lagged memory effects than MXD (Briffa et al, 2002;Anchukaitis et al, 2012), but also because RW may potentially integrate other ecological signals (e.g.…”

Section: Introductionmentioning

confidence: 99%

Experiments based on blue intensity for reconstructing North Pacific temperatures along the Gulf of Alaska

et al. 2017

Self Cite

View full text Add to dashboard Cite

Abstract. Ring-width (RW) records from the Gulf of Alaska (GOA) have yielded a valuable long-term perspective for North Pacific changes on decadal to longer timescales in prior studies but contain a broad winter to late summer seasonal climate response. Similar to the highly climatesensitive maximum latewood density (MXD) proxy, the blue intensity (BI) parameter has recently been shown to correlate well with year-to-year warm-season temperatures for a number of sites at northern latitudes. Since BI records are much less labour intensive and expensive to generate than MXD, such data hold great potential value for future treering studies in the GOA and other regions in mid-to high latitudes. Here we explore the potential for improving treering-based reconstructions using combinations of RW-and BI-related parameters (latewood BI and delta BI) from an experimental subset of samples at eight mountain hemlock (Tsuga mertensiana) sites along the GOA. This is the first study for the hemlock genus using BI data. We find that using either inverted latewood BI (LWB inv ) or delta BI (DB) can improve the amount of explained temperature variance by > 10 % compared to RW alone, although the optimal target season shrinks to June-September, which may have implications for studying ocean-atmosphere variability in the region. One challenge in building these BI records is that resin extraction did not remove colour differences between the heartwood and sapwood; thus, long term trend biases, expressed as relatively warm temperatures in the 18th century, were noted when using the LWB inv data. Using DB appeared to overcome these trend biases, resulting in a reconstruction expressing 18th-19th century temperatures ca. 0.5 • C cooler than the 20th-21st centuries. This cool period agrees well with previous dendroclimatic studies and the glacial advance record in the region. Continuing BI measurement in the GOA region must focus on sampling and measuring more trees per site (> 20) and compiling more sites to overcome site-specific factors affecting climate response and using subfossil material to extend the record. Although LWB inv captures the interannual climate signal more strongly than DB, DB appears to better capture long-term secular trends that agree with other proxy archives in the region. Great care is needed, however, when implementing different detrending options and more experimentation is necessary to assess the utility of DB for different conifer species around the Northern Hemisphere.

show abstract

“…The "Year without Summer," 1816, is a known cold period for the Northern Hemisphere following the eruption of Mount Tambora in 1815 (Stothers, 1984;Rampino & Self, 1982;Harington, 1992;Chenoweth, 1996;Anchukaitis et al, 2017). The "Year without Summer," 1816, is a known cold period for the Northern Hemisphere following the eruption of Mount Tambora in 1815 (Stothers, 1984;Rampino & Self, 1982;Harington, 1992;Chenoweth, 1996;Anchukaitis et al, 2017).…”

Section: Temperature Field Reconstructionmentioning

confidence: 99%

Multivariate Climate Field Reconstructions Using Tree Rings for the Northeastern United States

et al. 2020

Self Cite

View full text Add to dashboard Cite

High-resolution paleoclimate records are essential for improving our understanding of internal variability and the detection and attribution of forced climate system responses. The densely populated northeastern United States is at risk from increasing temperatures, severe droughts, and extreme precipitation, but the region has limited annual and seasonal-resolution paleoclimate records beyond the instrumental record. Chamaecyparis thyoides, L. (B.S.P.), Atlantic white cedar, a wetland conifer found within 200 km of the Atlantic coastline of the United States, is a promising tree-ring proxy that can fill in these data gaps. Here, we develop and analyze a new network of Atlantic white cedar tree-ring chronologies across the northeastern United States and demonstrate that site selection is important for regional paleoclimate reconstructions. Ring width variability reflects winter through summer temperatures at inland and hydrologically stable sites in the northernmost section of the species' range. Ombrotrophic sites along the coast record hydrological signals and correlate with growing season precipitation. We demonstrate skillful regional climate field reconstructions for the last several centuries and show the increased skill from incorporating our moisture sensitive sites into broad-scale products like the North American Drought Atlas. This comprehensive understanding of the species' climate responses leads to a tree-ring network that provides the long-term multivariate climate context at multidecadal and centennial time scales for the large-scale ocean-atmospheric processes that influence the climate of the region. We use this network to examine the covariance of temperature and drought across the New England area over the past two centuries.

show abstract

Last millennium Northern Hemisphere summer temperatures from tree rings: Part II, spatially resolved reconstructions

Abstract: Climate field reconstructions from networks of tree-ring proxy data can be used to characterize regional-scale climate changes, reveal spatial anomaly patterns associated with atmospheric circulation changes, radiative forcing, and large-

Cited by 199 publications

References 228 publications

A pseudoproxy assessment of data assimilation for reconstructing the atmosphere–ocean dynamics of hydroclimate extremes

A pseudoproxy assessment of data assimilation for reconstructing the atmosphere–ocean dynamics of hydroclimate extremes

Experiments based on blue intensity for reconstructing North Pacific temperatures along the Gulf of Alaska

Multivariate Climate Field Reconstructions Using Tree Rings for the Northeastern United States

Contact Info

Product

Resources

About